Inclosed dynamo-electric machine



n. P. THoMsQN INCLOSED DYNAM ELECTRIC MGHINE original Filed May 1. 1926Fig-L Inventor;

f-ILS Attorney.

" Dam FThoms'o" WM l Patented Dea 6,1921.- I UNITED STATES 1,652,134PATENT OFFICE.

DAVID P. THOMSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO4 GENERAL ELECTRICCOMPANY, A CORPORATION 0F NEW YORK.

INCLOSED DYNAMO-ELECTRIC MACHINE.

Substitute for joint application Serial No. 106,083, illed May 1, 1926.This Serial No. 202,954.

provision of an improved construction forsuch machines which, whilesimple and manufacturable at a relatively low cost, results in a greateroutput of the machine and in general a more satisfactory operation undercircumstances which require the use of this type of machine.

My invention will be better understood from the following descriptiontaken in connection with the accompanying drawing, and its scope will bepointed out in the appended claims. t

Referring to the drawing, Fig. 1 is a longitudinal sectional view of anembodiment of my invention and Fig. 2 is an end view of the same withparts broken away.

In the drawing the stator frame 1 is shown in the form of a cylinderhaving feet 2 and to this frame are fixed, as by bolts 3, the lieldpoles having the windings 4. The ro'- tor comprises the core structure 6mounted on the shaft 7 and carrying windings 8 having end turns 9 and10. The core structure 6 is provided with longitudinal Ventilatingopenings 11 near the shaft and similarly arranged openings 12 are alsoprovided in the commutator 13. At the commutator end, the shaft 7 isjournalled in the bearing 15 carried by the end head 16 which is securedto the stator frame 1 so as to make a tight joint therewith. The outerend of the bearing is shown closed by a plate 17 which also forms an oilwell for the bearing.

At the other end of the stator frame is the ring 2O and the end head 21which are secured together and to the frame by the bolts 22. End head 21carries the bearing 23 for the shaft and adjacent the bearing are air inlet openings 24. An annular plate 25 attached to the end head cooperateswith the outer fan to be described later in directing the cooling aircurrents.

rIhe outer periphery of the ring 20 is formed with a series of wideslots 28 which are closed except for their two ends by the band 29.Passages are thus formed through which cooling air is received from thespace within the end head 21 and is discharged in an axial directionover the exterior surface of the frame,l The slots 28 are so formedapplication filed July 1, 1927'.

that the outlet portions 30 are somewhat constricted, thereby formingnozzles for giving the discharged air a greater velocity. On the outerface of the ring 20 is the thin partition or end wall 32 being shownfixed thereto by screws 33 and being preferably of good heat conductingmaterial. This partition in cooperation with the ring 20, the frame 1and the end head 16 formsa closed chamber for the active elements of themachine. T he partition 32 has a central opening through which the shaftextends and with which the shaft makes a fairly close fit.

For stiifening the partition and for prevent-f ing possible buckling ofthe same, particularly during the assembly of the machine, I haveprovided stiffening ribs 34 which are shown secured to the partition bysmall rivets. Machines of this type are particularly well adapted foruse in locations where the surrounding air is lade-n with foreignmatter, such as moisture, dust, dirt, etc., which are detrimental to theactive elements of the machine. The closed chamber of such a machinemay, by simple means such as gaskets, be sealed against the entrance offoreign matter at all points except where the shaft projects therefrom.By arranging the joint between the rotatable and stationary members ofthe machine at the surface of the shaft as in the present construction,the length of the joint and the resulting liability to leak is reducedto a minimum. For most purposes a clearance of about 20 mils between theshaft and the partition is.

satisfactory. Where greater tightness is required such, for example, asin chemical works, the clearance space may be closed by a suitable`gasket.

For producing a circulation within the closed chamber I provide the fan36 fixed to the shaft as, for example, by a key and having a shroud 37.The fan blades are shown cut away at one side to receive the end turns 9of the rotor winding and the shroud overlies the outer ends of the endturns. By this construction a more effective circulation is producedfrom the openings 11 in the rotor core past the end turns 9 along theinner surface of the partition 32 where considerable heat is lost andback through the openings in and between the stator poles.

0n the outer side of the partition 32 and close thereto is the fan 40also fixed to the shaft and provided with the shroud 41. The blades ofthis fan are shown cut away on their outer sides and the shroud isarranged close to the plate 25 whereby a more effective `flow of coolingair is produced from the inlet openings 24 in the adjacent end head,along the outer surface of the artition 32 and finally out through thenozz es where it is blown over the outer surface of the stator frame andfollows the contour of the end frame 16.

The shrouds 37 and 41 are arranged substantially the same distance fromthe axis of the shaft so that the zones of air moving over the surfaceof the plate 32 at the hig est velocity inside and outside of themachine will be at substantially the same radial distance from the axisof the shaft 7 which insures the maximum rate of transfer of heat fromthe air within the machine to that circulated over the outside thereof.

In order to prevent foreign matter carried in the circulating airaccumulating on the plate 32, the fan blades 36 and 40 are arrangedclosely adjacent the surfaces on each side of the plate which causes arapid circulation of air directly over the surfaces.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

dynamo-electric machine having a rotor member comprising a shaft,.astator member comprising a casing forming a closed chamber including athin Wall of high heat conductivity attached to said stator member andprovided with an opening slightly larger than the diameter of saidshaft, a fan on each side of said wall secured to said shaft, each fanhavin blades conforming to the surface of said p ate and extendingclosely adjacent thereto, in order to force air on both sides of saidwall over the surfaces thereof in intimate contact therewith and tofacilitate a. rapid transfer of heat from the air inclosed in said casinto the air circulated over the outside thereo 2. A dynamo-electricmachine having a rotor member comprising a shaft, a stator membercomprising 'a casing forming a closed chamber including a thin Wall ofhigh heat conductivity att-ached to said stator member and provided withan opening slightly larger than the diameter of said shaft, a fan oneach side of said wall secured to said shaft, each fan comprising bladesattached to said saft extending radially from the shaft with edgesconforming to the shape of said wall, and each fan being provided with ashroud attached to said blades at the edges thereof remote from saidwall, in order to force air on both sides of said wall over the surfacesthereof in intimate contact therewith and to facilitate a rapid transferof heat from the air inclosed in said casing to the air circulated overthe outside thereof.

3. A dynamo-electric machine having a rotor member comprising a shaft, astator member comprising a casing forming a closed chamber including athin wall of high heat conductivity attached to said stator member andprovided with an opening slightly larger than the diameter of saidshaft, a fan on each side of said wall secured to said shaft, each fancomprising blades attached to said shaft extending radially from theshaft with edges conformling to the shape of said wall, and each fanbeino' provided with a shroud attached to said rblades at the edgesthereof remote from said wall and at the same radial distance from theaxis of said shaft, in order to force air on both sides of said wallover the surfaces thereof in intimate contact therewith and tofacilitate a rapid transfer 0f heat from the air inclosed in said casingto the air circulated over the outside thereof.

In witness whereof, I have hereunto set my7hand this twenty-ninth day ofJune, 192

DAVID P. THOMSON.

